Microsoft yesterday resumed delivery of Windows 10 previews to its Insider members after taking a break in the lead up to and immediate aftermath of releasing this year's one major upgrade.

The company issued build 14901 to those who had signed up for the "fast" ring, the track that provides the most frequent updates.

Microsoft had halted Insider previews prior to Aug. 2's "Anniversary Update;" build 14393, the last given to Insiders, was released on July 18, but was tweaked several times with last-minute fixes in preparation for a wider launch.

Anniversary Update, also known as 1607 -- Microsoft's year and month naming convention -- was tagged as build 14393.10.

Microsoft has stopped and restarted Insider builds before and after each major upgrade, including mid-2015's original and the November 2015 follow-up, taking three to four weeks to resume previews. And as it has previously, the first string of releases after 14901 will feature few visible changes. Instead, Microsoft will focus on the operating system's foundation, which the company calls "OneCore."

Dana Sarker, a software engineer in the Windows and devices group, and the public face of the Insider program, warned testers that they may encounter more bugs than usual in 14901 and its successors. Those unwilling to deal with that should revert to Insider's "slow" or "release preview" tracks, Sarker said in a post to a company blog.